Improve logging

lib-injection/auto_inject.rb

@@ -1,23 +1,27 @@
-return if ENV['skip_autoinject']
+return if ENV['DD_TRACE_SKIP_LIB_INJECTION'] == 'true'
 
 begin
   require 'open3'
 
-  _, status = Open3.capture2e({'skip_autoinject' => 'true'}, 'bundle show ddtrace')
+  failure_prefix = 'Datadog lib injection failed:'
+  support_message = 'For help solving this issue, please contact Datadog support at https://docs.datadoghq.com/help/.'
+
+  _, status = Open3.capture2e({'DD_TRACE_SKIP_LIB_INJECTION' => 'true'}, 'bundle show ddtrace')
 
   if status.success?
-    puts '[DATADOG LIB INJECTION] ddtrace already installed... skipping auto-injection'
+    STDOUT.puts '[ddtrace] ddtrace already installed... skipping auto-injection' if ENV['DD_TRACE_DEBUG'] == 'true'
     return
   end
 
   require 'bundler'
   require 'shellwords'
 
   if Bundler.frozen_bundle?
-    puts "[DATADOG LIB INJECTION] Cannot inject with frozen Bundler"
+    STDERR.puts "[ddtrace] #{failure_prefix} Cannot inject with frozen Gemfile, run `bundle config unset deployment` to allow lib injection. To learn more about bundler deployment, check https://bundler.io/guides/deploying.html#deploying-your-application. #{support_message}"
     return
   end
 
+  # `version` and `sha` should be replaced by docker build arguments
   version = "<DD_TRACE_VERSION_TO_BE_REPLACED>"
   sha = "<DD_TRACE_SHA_TO_BE_REPLACED>"
 
@@ -31,22 +35,17 @@
     end
 
   unless bundle_add_ddtrace_cmd
-    puts "[DATADOG LIB INJECTION] NO VERSION"
+    STDERR.puts "[ddtrace] #{failure_prefix} Missing version specification. #{support_message}"
     return
   end
 
-  puts "[DATADOG LIB INJECTION] ddtrace is not installed... Perform lib injection for dd-trace-rb."
+  STDOUT.puts "[ddtrace] Performing lib injection with `#{bundle_add_ddtrace_cmd}`" if ENV['DD_TRACE_DEBUG'] == 'true'
 
   gemfile   = Bundler::SharedHelpers.default_gemfile
   lockfile  = Bundler::SharedHelpers.default_lockfile
 
-  if gemfile.basename.to_s == 'gems.rb'
-    datadog_gemfile = gemfile.dirname + "datadog-Gemfile"
-    datadog_lockfile = lockfile.dirname + "datadog-Gemfile.lock"
-  else
-    datadog_gemfile = gemfile.dirname + ("datadog-#{gemfile.basename}")
-    datadog_lockfile = lockfile.dirname + ("datadog-#{lockfile.basename}")
-  end
+  datadog_gemfile  = gemfile.dirname  + "datadog-Gemfile"
+  datadog_lockfile = lockfile.dirname + "datadog-Gemfile.lock"
 
   require 'fileutils'
 
@@ -56,29 +55,23 @@
     FileUtils.cp lockfile, datadog_lockfile
 
     output, status = Open3.capture2e(
-      { 'skip_autoinject' => 'true', 'BUNDLE_GEMFILE' => datadog_gemfile.to_s },
+      { 'DD_TRACE_SKIP_LIB_INJECTION' => 'true', 'BUNDLE_GEMFILE' => datadog_gemfile.to_s },
       bundle_add_ddtrace_cmd
     )
 
     if status.success?
-      puts '[DATADOG LIB INJECTION] ddtrace added to bundle...'
+      STDOUT.puts '[ddtrace] Datadog lib injection successfully added ddtrace to the application.'
 
       FileUtils.cp datadog_gemfile, gemfile
       FileUtils.cp datadog_lockfile, lockfile
     else
-      puts "[DATADOG LIB INJECTION] Unable to add ddtrace: #{output}"
+      STDERR.puts "[ddtrace] #{failure_prefix} Unable to add ddtrace. Error output:\n#{output.split("\n").map {|l| "[ddtrace] #{l}"}.join("\n")}\n#{support_message}"
     end
-  rescue => e
-    puts "[DATADOG LIB INJECTION] trial error: #{e}"
   ensure
     # Remove the copies
     FileUtils.rm datadog_gemfile
     FileUtils.rm datadog_lockfile
   end
-rescue Bundler::BundlerError => e
-  puts "[DATADOG LIB INJECTION] BundlerError: #{e}"
-rescue LoadError => e
-  puts "[DATADOG LIB INJECTION] LoadError: #{e}"
 rescue Exception => e
-  puts "[DATADOG LIB INJECTION] Exception: #{e}"
+  STDERR.puts "[ddtrace] #{failure_prefix} #{e.class.name} #{e.message}\nBacktrace: #{e.backtrace.join("\n")}\n#{support_message}"
 end